This invention relates to a system for the generation and conversion of energy to electricity. More particularly, the present invention relates to an environmentally safe and economically effective manner of generating and storing energy until it is needed by using a regenerative energy storage and conversion system.
There are several currently available technologies that can be used by the wind energy industry for energy storage purposes. First, there are the conventional standby energy storage devicesxe2x80x94batteries. Besides being environmentally hazardous, batteries take up a lot of physical space. They must utilize either a direct current (DC) electrical generator or an inverter in order to reconvert from battery power to alternating current (AC) so that their power can be utilized by the existing power grid. Industrial batteries last an average of about 10 years and are very expensive to replace. They also suffer from corrosion, and sometimes can create fires and cause explosions. Eventually, batteries create a disposal problem and pose a health hazard for society.
Second, the electricity from a wind turbine can be utilized to run a water pump which can then be used to place water behind a storage dam. When the wind has stopped, one simply releases the water from the reservoir through a conventional hydroelectric mechanism to produce whatever electricity is required. This process can and does work if you find wind turbines situated next to an existing dam. Otherwise, this arrangement can be an extremely impractical and expensive method of storing wind energy for later production of electricity.
Third, the wind energy could be stored in the form of compressed air. Some firms have air compressors mounted in their wind turbines or on the ground to produce compressed air energy. Then, it is later released to run a compressed air motor/turbine to generate electricity. Again, in order to store copious amounts of this type of energy, one must find oneself adjacent to an abandoned mine or underground caverns. Otherwise, this endeavor is an extremely expensive proposition. Further, it is also an expensive proposition to run compressed air through a compressed air turbine (like a steam turbine) to turn an electrical generator because it requires huge volumes of energy to operate such a device.
Fourth, the energy may be stored in hydraulic accumulators. However, like the compressed air storage system, hydraulic accumulators are an expensive proposition relative to the large volume of stored oil energy (necessary to accomplish) the task of generating commercial amounts of electric energy.
Fifth, a flywheel, such as one of the newer, high speed, composite flywheels may be used to store energy. Flywheels are claimed to be an inexpensive and compact method of storing energy; however, the use of such high speed, composite flywheels pose both safety and engineering/technological obstacles that have yet to be solved for this application. For example, a flywheel of this high speed design must spin at 40,000 to 100,000 rpm in order for it to work properly, and it must be placed in a wind turbine at a height of 30 to 80 meters, which placement automatically limits the size of the device that can be used. As such, the flywheel actually appears to be an expensive and impractical proposition.
While all of these methods have been utilized in one form or another over the years, the wind industry has not thought to combine several of them in a packaged approach to comprise an effective regenerative energy storage and conversion system.
The present invention is conveniently and economically located on the ground where it can be easily installed, maintained and repaired. This invention has the ability to work in a very favorable manner with a wind turbine or stand alone in an industrial setting to provide electrical power to meet peak demands or provide back-up electric power generation without using fossil fuels.
Also, the invention may be used as a stand alone propulsion system that can power electrical devices and pumps, and/or power or augment existing conventional propulsion systems an example of which might be for ocean going tankers or large commercial ships. The present invention combines several of the wind energy industry""s techniques that, to date, have had little success with converting, storing, and regenerating any significant amount of energy.
The wind energy industry tests for the highest wind speeds at a potential site and then, knowing that a particular wind speed is available at that site during that time period, they build to meet that highest capacity. Unfortunately in most cases, the maximum wind energy is available only a fraction of the time. Regardless, the renewable energy industry boasts to the public about how many kilowatts they add to the grid, but the truth is that one must be realistic and review the actual recorded electrical output of the turbine on an annual basis. And after a thorough economic examination, one finds that this source of potentially free energy is neither reliable, nor efficient.
For example, if the rated output of the turbine is compared with the actual metered electricity produced, there is a huge disparity. And, if one compares that statistic with the 24 hours in a day that the wind energy device is available but not producing electricity, one can see a gap widening in not only rated capacity but also in that basic connection between the available energy needed to meet the needs of customers 24 hours a day. Available capacity rarely meets rated capacity, nor is it available much of the time when it is needed by the customer.
Since wind is not thought to be a dependable source of energy, it is useful to consider the overall percentage of time that wind turbines are producing electricity out of the 100% time that they are available. Statistics range from 15% to 23% in actual electric output per year compared to that 100% availability. However, in a comparison to coal (75 to 85%), natural gas (95%), or nuclear energy (75%), wind has the lowest actual electric output per year. Clearly, these other competitive sources of electric power have significantly higher rates of reliability. More importantly, every one of them is available 24 hours a day, seven days a week no matter what the weather conditions.
Other advantages of the invention are disclosed within the following description and drawings.